Heating unit for electrically energized cookers



May 23, 1950 B. AMES 2,508,357

HEATING UNIT FOR ELECTR'ICALLY ENERGIZED COOKERS Original zFiled May 31, 1946 2 Sheets-Sheet 1 May 23, 1950 B. AMES 2,508,357

HEATING UNIT FOR ELECTRICALLY ENERGIZED COOKERS Original Filed May 31, 1946 2 Sheets-Sheet 2 1750M?" ,8 waif 777265 Patented May 23, 1950 UNITED STATES PATENT DFFICE .zgsmgf'sm HEATING "UNrrron ELEQTKICALIJY 'ENERGIEED oooms Butler Antes, ifost'on, Mass.

Original a ps-l sso May '31, 1943. Serial N 673,267. Divided and t h is application August I9,IMZJSeriaIlNoflIESfiSG (cram-so) vide an electrically energized heating unit -designed :to emit radiations which are effective for cooking iood,:etc. A further object :is to provide an electrically energized heating unit designed to emit radiations whiehiare efiective iiordestroying or modifying *odors smoke resultant from cooking or oven cleaning operations. A further object is toi-provide sun-electrically energized-heating unit of extremely highsefiiciency but whiohis simplein construction and which has long effective life. A further object is to provide an electrically energized heating unit having the above \characteristics and which is capable of embodiment in a structure of oenvenient shape and dimensions. Other and iurther objects and advantages of the invention will be pointed out-in the following more detailed description and by reference to the accompanying drawings, wherein Fig. .1 is a plan view showing the improved heating unit of the present invention mounted in a suitable supporting sleeve;

Fig. 2 is a diametric section showing the heating unit separate :trom thesupport-ing sleeve, substantially on the line -22 -of Fig. 1

Fig. 3 is .a bottom view of the heating unit showing the arrangement of the resistance coils cover is inverted, l'iaving .its bottom uppermost I and having the cylindrical side wall TM. The bottom 68 has a plurality of apertures H (Fig. 1'.) shown as dlsposedat the same distance from the center of the cup. Within the upper cup and .held

in spaced relation to its bottom 69 is a reflector;

plate H of bright aluminum. This plate is downwardly convex, as shown in Fig. 2, with its edge slightly spaced from the bottom of the cup and having a central aperture 12. The marginal portion of this reflector plate II is heldi-n spaced 2 relation to th'e reap attern as by means of edits. 13 passing "through apertures in the plate and the :bottom is or the sup, refractory insulating washes b'eihg interposed lbetwe'en the cup and plate.

Insulated contaret bla de's M, and at max-em 1y secured to theiuppersm facefoi the cup bottom 69 by the bolts 'Th'e'se contact blades, "as shown sin Fig. 1.,%'are or maybe located 90apart. A protease-disk "I 01 wire mesh screen "is as ran ed substantially tire plane of the lower edge of the "wan to of the-rip er cup, anu is held in spaced a elation to the -icflector Tl by studs 73 fixed to the mm bottom 6'9. The screen disk "I l protects tlierefie'ctror "p' .t'e n from melting, and also aotsto refi'ect'ra'd on back toyvard the heat m elements, while the pram reflects b'ackth'e radiation's which pass threaten the screen. heated gases and vapors pass up around the xii-i cumierenc'e, and then rover the heateo surface of this aluminum plate M, and in close eontact therewith, which 5 is smaller in diameter than the cup in'whieh itzisheld, and then pass out through the holes Tl in the our) bottom.

The outer 'oriower cup which forms the lower art "of tire casing of the heating unit of Ialrge'i' diameter than the upper cup and is arranged in concentric relation to the latter with the cylindries-1 wan or the lower one surroundin but spa'cedifrom thewaill In "of the upper'cu p 'amdwitn the b'ottomltfl of the lower oup spaced from the disk 71. The -bottom of the lower cup has a large eentral aperture 81., the margin of this aperture having unturned "tabs '82 which en age disk 84 has an upturned flange 85 at its edge which bears against the under surface of the cup bottom 86, and is preferably provided with cohcentric annular corrugations providing a series of concentric grooves 86 in its lower surface. While these grooves are here shown as oonce'n tri'c, it is'within the purview of the invention to provide a single spiral groove instead of the series of concentric grooves.

Within these grooves there are disposed a plu rality of insulating grommets or spool like sleeves 81 (Fig. 330i refractory, electrical insulat ing material, for example, porcelain, each groin met having a. o'entral barrel portion 88 (Fig. 3)

The grommets constitute insulating supports for the resistance coils 9| and 92, which may be of any of the usual materials employed for this purpose. Not only do the corrugations in the screen disk 94 provide cradles for the grommets,

said unit comprising a shallow metallic cup having an annular flange, a fire mesh screen united at its edge to said flange, insulating means supporting a resistance element closely adjacent to and at the outer side of the screen, a second screen within the cup and parallel to but spaced and have their ends united above the screen.

from the first screen, refractory material coating the constituent wires of the two screens but leaving the screen mesh open, and a metallic refiecting element within the cup at the inner side :.of the second screen and spaced from the latter,

- the edge of said reflector element being spaced from the side wall of the cup. and the cup bottom *having an opening therein for the escape of but they also serve to spread the radiations from i the heating elements throughout the oven.

As illustrated in Fig. 3, the grommets which support the coils 9| and 92, are arranged in a spiral series, the turns of one spiral series being interposed between those of the other. The grommets are preferably arranged in groups, as shown in Fig. 3, so as to expose unobstructed arcs of the resistance coils of as great a length as is consistent with adequate support.

'-,-One end 93 (Fig. 3) of the coil 9| is passed through a refractory insulating sleeve 94 set in the screen 84 and through a refractory sleeve in the screen 17 and is then attached to one of the bolts l3 which anchors the contact blade 14 to the cup bottom 69. The opposite end 95 of coil 9| passes through an insulating sleeve 96 at the center of the screen disk 84 and through a second insulating sleeve in the screen 11 and is electrically connected to contact blade 15. The inner end 91 of coil 92 is likewise connected to contact lade 15, while its opposite end 98 passes through insulating sleeves in the screens 11 and 84 and is electrically connected to the contact blade IS.

The screen disk 84- and the insulating grommets 81 (after the latter have been attached to the screen disk) are coated, for example by spraying or dipping, with a refractory cement 99 suchas Alundum (Fig. 4). The screen is then baked to harden the cement. This coating covers the grommets and the constituent wires of the screen,

but does not completely close the openings in the screen, as shown in Fig. 4. Through these openings in this screen, and close to the heating elements, must pass all the airborne products of cooking, whether the door of the cooker is closed or open, and are so brought in close proximity to the radiations that destroy or change them. The screen disk 11 is preferably coated in the same manner with a refractory cement.

' While one desirable embodiment of the inven-' screen, a resistance heating element carried by said. insulating elements, a second screen spaced from and parallel to the first, refractory material coating the constituent wires of the two screens while leaving their meshes substantially unobstructed, and a reflector element parallel to and spaced from the second screen.

- '2. A heating unit for use in an electrical cooker;

.gaseous material. -3. A heating unit for use in an electrical cooker, said unit comprising two shallow opposed cups telescoped one within the other, the inner cup being inverted, each cup having substantially cylindrical side walls, the bottom of the inner cup having a plurality of apertures for the passage of gases, a reflector plate having a central aperture disposed within the inner cup with its edge spaced from the cylindrical wall of the cup, means holding the reflector cup spaced from the bottom of the inner cup, the bottom of the outer cup having a central aperture, a foraminous disc disposed below the bottom of the outer cup, and refractory supports for a resistance element attached to the underside of said foraminous disc.

4. A heating unit for an electrical cooker, said unit comprising a shallow cup having a large central aperture in its bottom, a disc of foraminous material disposed below the cup bottom, a. plurality of insulating supports attached to the underside of the disc, resistance elements carried by the supports, reflector means within the cup, a cover element overlying the reflector element, and means uniting the several parts in assembled relation. 5. A heating unit for electrical cookers, said unit comprising a hollow case having top and bottom walls, the bottom wall having a large central aperture, a disc of wire mesh material disposed below the aperture in the bottom wall or the case, a plurality of refractory insulating supports attached to the underside of the disc, a' second foraminous disc arranged within the case and parallel to the first disc, an annular reflector plate disposed above and spaced from the foraminous disc within the case and means uniting the parts in assembled relation.

6. A heating unit for electrical cookers, said including a shallow cup-like bottom member and up through the disc, shield and plate and being connected to the contact blades, means for insulating the terminals of the resistance wire from the disc, shield and plate, and means uniting the (References on following page) 5 summons cum) t??? The following references are of record in the 2:237:094 file of this patent:

UNITED STATES PATENTS 5 Number Number Name Date 279,418 1,220,181 Plrkhurlt Mar. 27, 1917 493,533

6 Name Date Howard et a1. Sept. 17, 1940 Aske "Apr. 1, 1941 FOREIGN PATENTS Country Date Italy Nov. 12, 1980 Great Britain Jan. 4, 1937 

